DG-400 und DG-600 – the fore-runners of our DG-800

When a customer wants to buy a used DG-400 or DG-600, we are often asked, what are the special characteristics of these aircraft.  For this reason, we would like to make a few remarks about these fore-runners of the DG-808.

A.  DG-400:

Today the DG-400 is still the most numerous of the flapped models of self launching sailplanes in the world with 280 built.  This place of honor is expected to be given up to the DG-800 in the year 2002.  The engineering on this model can be called fully developed for its time.  The costs of repair may thus be limited.  One limitation must however be mentioned:
The Rotax Company does not make the engine anymore.
The airfoil of the DG-400 is somewhat older.  It goes back to the DG-200 which was developed in 1977.  A 17 meter, carbon fiber version was used in the motorized DG-400.  This makes the DG-400 uncompetitive in today’s contests.  But for cross country and entry into the flapped motor glider scene it is ideal.  The glide angle of 42:1 is still quite good and much of what a DG of today does, the ‘400 can also do.  Especially nice is the large canopy with its good visibility and which affords warm feet for flying in winter and at high altitudes.
The noise limiting techniques used in the ‘400 are not up to today’s standards.  The outside motor is somewhat uncomfortable in loudness but it still is within the limits of the “increased noise standards” and therefore still usable in Germany.  The reason for this is not because the motor is so quiet but rather that the noise measuring point is under the aircraft where it is shielded by the wings.
With respect to the radiation of higher frequencies from the engine down to the ground, a significant improvement can be made through the installation of sound absorbent covering.  This has been used by DG for some time.  It is well worth it and especially valued by the neighbors of the airport.
I flew my DG-400 for six years with great enjoyment but never in the 15 meter configuration.  Why?  Simply because it flew better at 17 meters!
At today’s prices for used sailplanes, you can get a lot of glider for your money and often with complete equipment.

B.  DG-600

There are three very different models of the DG-600:

  • DG-600/15 m FAI Class Course ( with winglets)
  • DG-600/17 m+ (with attachable tips)
  • DG-600M

The airfoil of the DG-600 is much more modern with higher performance than that of the DG-400.  It was designed in 1987 and in certain aspects similar to the one used in the DG-800.  With one exception:  The final choice was between a “conservative” layout and a second, higher performance design which could present problems during slow flight.  The higher performance, thinner airfoil was chosen and the suspected slow flight problem became evident.  At least in the 15 meter version, the stick of the DG-600 belonged in the hand of an experienced pilot because when one thermalled too slowly or recentered too often, the climb rate suffered.
Also the tendency to stall was not up to today’s standards.  Because of this, the LBA mandated a “Stall Warning” placard.  These flying characteristics gave the glider a bad name and so it was never a great success.  As an indication of how well a DG-600/15 m can be flown, a new world record was recently flown.  (100 km triangle at 182.4 km/hr).
The 17 m version with is quite a different story.  It has been increased to 18 meters and even winglets can be added at this span.  At this larger span and by the winglets the behavior at stall is nearly harmless and significantly more acceptable.  The performance at high speed is as good as the DG-800.  Only in climb, is the ‘800 better while retaining good flight characteristics!
A DG-600/18 m with winglets is, without question, competitive in the 18 meter class.
A new fuselage was developed for the DG-600 with a low drag, narrow waist behind the cockpit.  Only minor modification of this fuselage was made when it was adapted to the DG-800S.  In order to mount a motor in the DG-600, a very small, one cylinder Rotax engine was used.  The resulting DG-600M was capable of self launching but with only 25 Hp, the rate of climb is pretty slim.  Because of the motor’s small size, the noise level measurements were also low when it flew over the measuring point giving a value within the German “ordinary noise level” definition.  Certain restrictions on weekends apply.
In conclusion, a DG-600M can be bought for less money than a DG-808B and you get a glider with similar flight performance which can self launch off longer runways and get home when the thermals quit.
The wing moulds for the DG-600 were destroyed in a fire at the factory in 1992 so only 112 units were built.